Perhaps you should try some spelling variations:
"nijhoff book title 25" » "nijhoff boston title 25", "nijhoff op title 25", "nijhoff book titles 25", "nijhoff book table 25", "nijhoff work title 25", "nijhoff book title 2", "nijhoff book title 5", "nijhoff book title 26"
"nijhoff ebook title 20" » "nijhoff book titles 20", "nijhoff ebook titles 20", "nijhoff ebook table 20", "nijhoff ework title 20", "nijhoff ebook title 2", "nijhoff ebook title 10", "nijhoff ebook title 26"
"nijhoff ebook title 21" » "nijhoff book titles 21", "nijhoff ebook titles 21", "nijhoff ebook table 21", "nijhoff ework title 21", "nijhoff ebook title 1", "nijhoff ebook title 2", "nijhoff ebook title _"
"nijhoff ework title 20" » "nijhoff work title 20", "nijhoff work titles 20", "nijhoff works title 20", "nijhoff ework title 2", "nijhoff ework title 10", "nijhoff ework title 26"

You may be able to get more results by adjusting your search query.

• If you are trying to use Boolean operators, they must be ALL CAPS: (((((("nijhoff ebook title 20") OR ("nijhoff ework title 20"))) OR ("nijhoff ebook title 21"))) OR ("nijhoff book title 25")).
• The words AND, OR and NOT may confuse the search; try adding quotes: "((((((\"nijhoff ebook title 20\") OR (\"nijhoff ework title 20\"))) or (\"nijhoff ebook title 21\"))) or (\"nijhoff book title 25\"))".
• Removing quotes may allow a broader search: (((((( nijhoff ebook title 20 ) OR ( nijhoff ework title 20 ))) or ( nijhoff ebook title 21 ))) or ( nijhoff book title 25 )).
• Adding a wildcard symbol may retrieve word variants: (((((("nijhoff ebook title 20") OR ("nijhoff ework title 20"))) or ("nijhoff ebook title 21"))) or ("nijhoff book title 25"))*.